Dental prostheses are commonly used in the repair of tooth damage that does not lend itself to simple fillings. Dental restoration presents many challenges. The tooth replacement or restoration material must conform as much as possible to the original function, shape, color, and texture of the tooth to be repaired or replaced. In particular post-processing steps such as finishing and polishing of dental restorations are important in any restorative procedure and can impact the aesthetics and longevity of the prosthesis. Improper post-processing can result in undesirable surface roughness or smoothness with impacts on such clinical outcome as plaque formation, gingival inflammation, and poor aesthetics.
The techniques used in dental restoration have evolved considerably over the past few decades. Traditional manual fabrication, which involves the acquisition of teeth impressions that are used by a technician to fabricate the dental restoration, is time consuming and of limited scope for finishing the final product. For example surface finish roughness of mechanically milled restorations often does not meet aesthetic and clinical requirement and requires manual polishing or glazing steps. Localized coloration and translucence needs to be adjusted manually by applying coloured glaze and stains. These additional materials may have limited durability and the post processing is time consuming.
More recent technologies such as computer assisted design/computer assisted manufacturing (CAD/CAM) systems offer more flexibility, precision and are less time consuming. However these systems also have limitations. In particular the current technologies are not optimized for the post-processing of the prosthesis to achieve superior appearance and texture. For example Selective Laser Sintering and Selective Laser Melting, two examples of layered additive manufacturing processes used in automated restoration production can result in the distortion in the underlying dental material due contraction/expansion of the material as a result of the thermal gradient generated by the thermo-physical process. In fact laser treatments of dental material disclosed have not been successful in providing a finished surface with adequate properties. Likewise conventional Computer Numerical Control (CNC) milling processes, which represents the most common automated process for dental prosthetic production, can also leave undesirable surface effects that must be removed by manual polishing.
In order to optimize such processes, complex processing algorithms are typically elaborated based on empirical data and theoretical simulations. However such automated methods are limited in their flexibility to adapt to particular conditions and design needs. There is therefore a need for improved systems and methods to reduce the time, cost, and variability in creating dental prostheses with acceptable surface characteristics with little or no manual effort.